Mechanistic Insights into Catalytic Cyclopropanation by Copper(I) Phosphine Complexes
X-ray crystal structures of [Cu(FBF₃)(PCy₃)₂] (Cy = cyclo-C₆H₁₁) and [Cu(MeCN)21,2-C6H₄CH₂NMe₂(PPh₂)]BF₄
The complexes [Cu(PPh3)n(MeCN)4-n]BF4 (n = 0, 2-3), [Cu(CBF3)(PCy3)2], [Cu(MeCN)21,2-C6H4CH2NMe2(PPh2)]BF4 and species formed by in situ addition of various ligands to [Cu(MeCN)4]BF4 are all active catalysts for cyclopropanation reactions using N2CH(CO2Et). With styrene as a substrate the trans/cis selectivity in the product cyclopropane may be somewhat controlled by the appropriate choice of phosphine ligand. Catalysis by [Cu(MeCN)2(PPh3)2]BF4 and [Cu(MeCN)21,2-C6H4CH2(PPh2)]BF4 is proposed to involve alkene coordination, while that by [Cu(MeCN)(PPh3)3]BF4 and [Cu(FBF3)(PCy3)2] is not. The structures of the catalysis showing the highest selectivity have been determined. For monoclinic [Cu(FBF3)(PCy3)2] the molecule contains on unusually large PCuP angle (ca 160°). © 1993.
J. C. Green et al., "Mechanistic Insights into Catalytic Cyclopropanation by Copper(I) Phosphine Complexes," Polyhedron, Elsevier, Jan 1993.
The definitive version is available at http://dx.doi.org/10.1016/S0277-5387(00)87175-2
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